1. Field of the Invention
This invention relates to thickening agents for alpha-olefin sulfonate surfactants and particularly to alpha-olefin sulfonate shampoo and liquid soap formulations which are thickened with a novel thickening agent.
2. Discussion of the Prior Art
Cleaning compositions, such as soaps and shampoos, containing alpha-olefin sulfonate surfactants have become increasingly popular in recent years in view of their low cost relative to alcohol sulfates, such as sodium lauryl sulfate which is generally considered to be the dominant surfactant in liquid cleaning compositions. The popularity of the alpha-olefin sulfonates (AOS) has been made possible by the development of the continuous falling film process using continuous thin-film reactors employing gaseous SO.sub.3, such as described, for example, in U.S. Pat. No. 3,142,169 to Knaggs and Nussbaum. However, because of their different chemical properties and formulating properties from the alcohol sulfates, for example, their viscosity response characteristics and foaming characteristics, the use of AOS surfactants has not been as widespread as possible.
It is generally known that the formulating characteristics of AOS surfactants can be modified to more closely correspond to that of the alcohol sulfate salts, such as sodium lauryl sulfate, by control of such variables as pH, salt level and type of salt, selection of foam boosting aids, and the like. The use of C.sub.10 -C.sub.15 primary alkanols for producing rich, stable, creamy wet lathers from AOS formulations is taught in U.S. Pat. No. 3,870,660 to Paviak. Nevertheless, the problem still remains in that none of the known thickening agents or thickened AOS formulations are capable of providing stable compositions with sufficiently high viscosities. Still further, the foaming characteristics of conventional alpha-olefin sulfonate formulations have not been entirely satisfactory.
Accordingly, it is an object of the present invention to provide alpha-olefin sulfonate containing formulations with viscosities as high as or higher than alcohol sulfate salts or other surface-active agents.
It is another object of the present invention to provide thickened shampoo and liquid soap formulations based on alpha-olefin sulfonate surface-active agents having viscosities of at least 200 cps and which produce thick and stable foams.
It is still a further object of the present invention to provide alpha-olefin sulfonate shampoo formulations of improved stability, foam richness, texture and wet combing properties.
It is still a further object of the present invention to provide a thickening agent for alpha-olefin sulfonate containing shampoos, liquid soaps and other cleaning formulations to provide a rich, thick, stable lather type foam.